The wet weather over the past couple of years has prompted reports of poor harvests, smaller and less tasty fruit and veg and claims that the nutrients the rain has washed away from the soil will affect the health value of our home-grown produce.

Among the crops worst hit in vegetable patches across the country is the humble spud, a staple of the British menu for centuries, whether boiled, mashed or chipped.

And while gardeners throughout the UK will be celebrating National Potato Day on January 27 with events up until the end of the month, experts are now warning that gardeners must start to grow a mixture of varieties to stem the loss of crops to late blight.

Affected plants develop brown spots, especially around the edges of the leaves, the stems turn brown and potatoes develop scabby cankers that lead to brown patches inside the tubers which soon rot.

Bob Sherman, chief horticultural officer of charity Garden Organic, warns: “Rare types of potatoes are under threat. There isn’t much that the amateur gardener can do to protect potatoes from blight.

“Late blight is a very rapidly-evolving organism. It’s not quite a fungus. It’s quite closely related to seaweed, but it acts like a fungus. Spores flow about in the air, usually coming from old tubers left in the soil which haven’t been harvested from the previous year because they’ve been missed.

“Most of the old varieties of potato are highly susceptible and even ones that were thought to be resistant have succumbed to new strains of the disease. We used to think that ‘Cara’ was blight-resistant, but it isn’t any more. A whole range of interesting textures and flavours from old varieties are under threat.”

Incessant wet weather causes both disease and physical problems with potatoes, he continues. The tubers can’t be lifted because the ground’s too heavy and soggy.

“When potatoes get too much moisture, you might get one or two huge potatoes under the soil instead of a nice little clump of medium-sized tubers. Dry weather tends to enhance flavour, but wet weather reduces it.”

Late potato blight has been the scourge of crops during excessive wet weather, he says.

However, some gardeners have turned to a resistant variety which is keeping blight at bay.

David Shaw, research director of the not-for-profit Sarvari Research Trust in North Wales, and his team developed a range of blight-resistant ‘superspuds’ known as Sarpos (pronounced Sharpo), first bred by the Hungarian Sarvari family.

Available in red, white and blue, from Thompson & Morgan and some garden centres, they are now being grown by gardeners who don’t want the plight of blight.

“The disease evolves all the time, a bit like flu, so there’s always a new strain. The Sarpo varieties David Shaw has been working with seem to be coping with all the changes that the disease is going through,” says Bob.